These guidelines are intended for the growing number of information services which use, or plan to use, a multilingual thesaurus. The purpose is to describe the various tasks involved in constructing and developing multilingual thesauri, and where possible, to recommend standard practices. The scope is restricted to a consideration of the problems of multilingualism as they relate to conventional thesauri--those intended for use by human indexers and searchers, designed for coordinate indexing, and which avoid semantic factoring. There is emphasis on thesauri which distinguish between descriptors and non-descriptors. Guidelines are based on experience gained in the fields of science and technology and they concentrate on the world's major languages in these fields. Definitions, methods of use and thesaurus construction, basic problems of multilingual thesauri, presentation and arrangement, the process of constructing multilingual thesauri, and organizational aspects are considered. (Author/KP)